He added: ‘This concert’s to celebrate life. To say ‘No’ to terrorists’.

The Champs-Elysees gunman, named as Karim Cheurfi, who shot and killed a police officer just days before France’s presidential election was detained in February for threatening police.

He was later freed.

Cheurfi, a 39-year-old French national, was also convicted in 2003 of attempted homicide in the shootings of two police officers.

Karim Cheurfi opened fire on police on Paris (Picture: AP)

French municipal policemen observe a minute of silence on April 21, 2017 (Picture: Getty)

The French government pulled out all the stops to protect Sunday’s vote as the attack deepened France’s political divide.

‘Nothing must hamper this democratic moment, essential for our country,” Prime Minister Bernard Cazeneuve said after a high-level meeting Friday that reviewed the government’s already heightened security plans for the two-round presidential vote that begins Sunday.

‘Barbarity and cowardice struck Paris last night,’ the prime minister declared, appealing for national unity and for people ‘not to succumb to fear.’

Investigators believe at this stage that the gunman, 39-year-old Frenchman Karim Cheurfi, was alone in killing one police officer and wounding two others and a female German tourist on Thursday night, a French official who discussed details of the investigation with the AP said on condition of anonymity.

The attack came less than 72 hours before the polls open.

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Police investigators inspect the car used by the attacker on the Champs Elysees Avenue after two policemen were killed and another wounded in a shooting incident in Paris (Picture: Reuters)

Police shot and killed Cheurfi after he opened fire on a police van on Paris’ most famous boulevard.

Investigators found a pump-action shotgun and knives in his car. Cheurfi’s identity was confirmed from his fingerprints.

Cheurfi had been detained toward the end of February after speaking threateningly about police but was then released for lack of evidence, according to that French official and another, who also spoke on condition of anonymity because they weren’t authorized to publicly discuss the probe.